Facebook founder Mark Zuckerberg came to Washington a few weeks ago to absorb the wrath of a Congress angered by the way his company allowed the political consultancy Cambridge Analytica to harvest the personal data of millions of unsuspecting Facebook users.

A few members of Congress understood that the outrage was even greater: that Zuckerberg’s company basically exists in order to spy on us. That it tracks us as we wander online. That it controls the news users see. That it buys up competitors and operates as a near monopoly. That this panopticon corporation (whose services I myself use every day) has more power – political power, cultural power – than any private entity ought to have. As Zephyr Teachout put it, the company is “a danger to democracy”.

Understanding this, some in Congress were pretty tough on Zuckerberg. But watching him squirm under the Washington glare reminded me of a different conversation between the young billionaire and an elected official, one that took place in the summer of 2016, back when a sunnier conception of Facebook was mandatory among America’s enlightened class.

The setting was the state department’s annual “Global Entrepreneurship Summit”, the elected official was President Barack Obama, and the object seems to have been to deliver a thinly disguised advertisement for Facebook as a lovable facilitator of basic human relationships.

Seated with a panel of entrepreneurs from around the world, the president lobbed his friend Zuckerberg an easy question about Facebook “creating this platform for entrepreneurship around the world”. In batting it out of the park, the Facebook CEO, clad in his humble costume of jeans, T-shirt and sneakers, took pains to inform everyone that what animated him were high-minded ideals. “When I was getting started,” he burbled, “I cared deeply about giving everyone a voice, and giving people the tools to share everything that they cared about, and bringing a community together …”

No rude senator spoke up to interrupt this propaganda. Instead, Zuckerberg went on to describe his efforts to connect everyone to the internet as a sort of wager on human goodness itself.

“It’s this deep belief that you’re trying to make a change, you’re trying to connect people in the world, and I really do believe that if you do something good and if you help people out, then eventually some portion of that good will come back to you. And you may not know up front what it’s going to be, but that’s just been the guiding principle for me in the work that we’ve done …”

That’s how it works, all right. Gigantic corporate investments are acts of generosity, and when making them, kind-hearted CEOs routinely count on Karma to reward them. That’s the “guiding principle”.

Reader, here is what the president could be heard to say as Zuckerberg ended this self-serving homily: “Excellent.”

I bring all this up not to ding Obama participating in a corporate whitewash, but to remind liberals and Democrats that, until very recently, this was who we liberals were. We drank the Kool-Aid. We believed the hype. Facebook wasn’t a “danger to democracy”, we thought. Facebook was democracy.

Do you remember? The 2008 campaign, which elevated Obama to the White House, was described by the enlightened as “the Facebook election”. We had seen a community organizer, ably assisted by a Facebook co-founder, win the presidency by organizing communities – by organizing them online! The combination of idealistic togetherness and awesome futurific-ness was thought to be too much for those plodding, selfish Republicans.

Obama’s state department, led by Hillary Clinton, became the country’s main institutional proponent of the thesis that, wherever the internet went, there also went markets, and entrepreneurship, and liberation. Clinton called the state department’s new mission “internet freedom” (she introduced the idea in a speech given, ironically, at a museum of journalism); she intended to take what she called a “venture capital approach” to the problem of overcoming state censorship and battling the tyrants of the world.

I was exposed unforgettably to liberal techno-optimism at a Clinton Foundation event in March 2015, when I heard a speaker hail social media as the ally and liberator of the female population of the entire planet. Or think of the way Obama surrounded himself with transplanted Silicon Valley types in the last years of his administration; or of Clinton’s 2016 campaign, run by an algorithm; or of Clinton’s rumored intention to make Sheryl Sandberg, Facebook’s No2, her treasury secretary.

But then the narrative went all wrong. Instead of overthrowing unsavory regimes in the Middle East, the internet overthrew its high-minded comrades in the Democratic party. It turned out that even an obtuse cad like Donald Trump could tweet. Errant emails caused countless headaches. Mean Russian trolls published crazy things on Facebook. And finally … Cambridge Analytica, harvesting people’s personal data. What an ingrate the internet has turned out to be.

Today the Democratic party stands at the crossroads, and I hope the awful experience of 2016 will at least make them think twice before they resume their devotions in the First Church of Silicon Valley. Maybe they are finally ready to think a little harder about what democracy means. To stand up, at long last, for we the surveilled.

• Thomas Frank is a columnist for the Guardian US